This application relates to a rack and pinion connection for use in a manual wrench drive for an air starter valve.
Air starter valves are known, and are utilized in conjunction with gas turbine engines to provide air to the starter when the engine is being started. The flow of air to the starter is stopped by the starter air valve once the engine has started.
In one known air starter valve, a manual wrench drive allows movement of the valve for maintenance, or for repair. The valve is normally moveable upon control of a solenoid valve. However, should the valve fail, the manual wrench drive can also move the valve to an open position.
The manual wrench drive typically drives rotation of a pinion gear which in turn drives rack teeth associated with a shaft to move a valve skirt. The rack has generally been machined into a cylindrical portion of the shaft which is connected to the valve skirt. The valve skirt, shaft, and rack, as a unit, were able to rotate relative to the housing.